12. air Quality impact

Introduction

12.1 An impact assessment of air quality impacts associated with the construction phase of the Project is presented in this section. Representative Air Sensitive Receivers (ASRs) in the vicinity of the Project site are identified. Potential air quality impacts arising from construction work sites, concrete batching plant, temporary magazine sites, stockpiles and barging facilities have been assessed and appropriate mitigation measures are recommended.

12.2 The XRL is an electric railway, therefore, no air pollutants emissions generated within the rail system is expected. However, it may have diesel locomotives to be operated at Shek Kong Stabling Sidings (SSS). The air quality implication in connection with the operation of these diesel locomotives is presented in this section. A public transport interchange (PTI) will be provided at the ground floor of Ventilation Building Complex (next to West Kowloon Terminus) during the operation phase. The air quality inside the PTI is also addressed.

Environmental Legislation, Standards and Guidelines

12.3 The criteria for evaluating air quality impacts and the guidelines for air quality assessment are laid out in Annex 4 and Annex 12 of the EIAO-TM as well as the requirements set out under Clause 3.4.1 of the EIA Study Brief.

Air Quality Objective & EIAO-TM

12.4 The Air Pollution Control Ordinance (APCO) provides the statutory authority for controlling air pollutants from a variety of sources. The Hong Kong Air Quality Objectives (AQOs), which stipulate the maximum allowable concentrations over specific periods for typical pollutants, should be met. The relevant AQOs are listed in Table 12.1.

Table 12.1 Hong Kong Air Quality Objectives

	Maximum Concentration (µg m^-3) ^(1)
Pollutant	Averaging Time
	1 hour ^(2)	8 hour ^(3)	24 hour ^(3)	Annual ^(4)
Total Suspended Particulates (TSP)	^-	-	260	80
Respirable Suspended Particulates (RSP) ^(5)	-	-	180	55
Sulphur Dioxide (SO2)	800	-	350	80
Nitrogen Dioxide (NO2)	300	-	150	80
Carbon Monoxide (CO)	30,000	10,000	-	-
Photochemical Oxidants (as Ozone, O3) ^(6)	240	-	-	-

Note:

(1) Measured at 298 K and 101.325 kPa.

(2) Not to be exceeded more than three times per year.

(3) Not to be exceeded more than once per year.

(4) Arithmetic mean.

(5) Suspended particulates in air with a nominal aerodynamic diameter of 10 mm or smaller.

(6) Photochemical oxidants are determined by measurement of ozone only.

12.5 The EIAO-TM stipulates that the hourly TSP level should not exceed 500 mgm^-3 (measured at 25^oC and one atmosphere) for construction dust impact assessment. Mitigation measures for construction sites have been specified in the Air Pollution Control (Construction Dust) Regulation.

Air Pollution Control (Construction Dust) Regulation

12.6 Notifiable and regulatory works are under the control of Air Pollution Control (Construction Dust) Regulation. Notifiable works are site formation, reclamation, demolition, foundation and superstructure construction for buildings and road construction. Regulatory works are building renovation, road opening and resurfacing, slope stabilisation, and other activities including stockpiling, dusty material handling, excavation, concrete production, etc. This Project is expected to include notifiable works (foundation and superstructure construction) and regulatory works (temporary stockpile, dusty material handling, excavation and concrete production). Contractors and site agents are required to inform EPD and adopt dust reduction measures to minimize dust emission, while carrying out construction works, to the acceptable level.

Air Pollution Control Ordinance - Control of Emissions from Specified Processes

12.7 The operation of the following facility is classified as Specified Processes (SP) under the APCO and is subject to a more stringent emission control.

· Operation of Cement Works in which the total silo capacity exceeds 50 tonnes and in which cement is handled or in which argillaceous and calcareous materials are used in the production of cement clinker, and works in which cement clinker is ground.

12.8 A licence is required for the operation of the Cement Work (Concrete Batching Plant) under Part IV of the ordinance. Application for licence should be made to EPD. EPD may either grant or refuse to grant a licence subject to whether the applicant can fulfil the environmental standards to avoid causing air pollution. If EPD decides to grant the licence, a set of conditions will be imposed to prevent adverse impact from the discharge of air pollutant emissions.

PTI Air Quality Guideline

12.9 The air quality guideline of PTI is stipulated in EPD’s ProPECC PN1/98 Control of Air Pollution in Semi-confined Public Transport Interchanges, which recommend the maximum allowable concentration of pollutants in a semi-confined PTI. The PTI Air Quality Guideline is shown in Table 12.2 below.

Table 12.2 PTI Air Quality Guideline

Pollutant	Maximum Concentration not be exceed (µg m^-3) ^(1)
	1 hour average (mg/m^3)	5-minute average (mg/m^3)
Carbon Monoxide (CO)	30,000	115,000
Sulphur Dioxide (SO2)	800	1,000
Nitrogen Dioxide (NO2)	300	1,800

Note:

(1) Expressed at the reference condition of 25°C and 101.325 kPa.

Description of the Environment

12.10 The Project alignment runs from Huanggang (Mainland) beneath Mai Po, Ngau Tam Mei, Kam Tin, Tai Mo Shan and Kwai Chung, Lai Chi Kok, Nam Cheong and Tai Kok Tsui to the West Kowloon Terminus (WKT). The main land uses of Mai Po, Ngau Tam Mei, Kam Tin, Tai Mo Shan are rural area; and villages / low density developments. The areas in Kwai Chung, Lai Chi Kok, Nam Cheong, Tai Kok Tsu and West Kowloon Terminus are urban areas and the main land uses are residential, commercial and educational institutes.

12.11 A total of eight ventilation buildings will be located in the New Territories (i.e. Mai Po, Ngau Tam Mei, Pat Heung) and western side of Kowloon (i.e. Shing Mun, Kwai Chung, Nam Cheong, Mong Kok West and West Kowloon). Emergency access point (EAP) will be integrated at these ventilation buildings and there is a building in Tai Kong Po for emergency services. Ventilation shafts will also be provided to serve for West Kowloon Terminus (WKT).

12.12 Stabling Sidings and maintenance facility will be located at Shek Kong to provide stabling and maintenance and cleaning activities. An emergency rescue station (ERS) will be located next to Shek Kong Stabling Sidings (SSS) for evacuation of passengers and access by emergency personnel to deal with incidents.

12.13 Site visits were conducted from August to September 2008 to investigate the baseline environment in the vicinity of the WKT, ventilation buildings and SSS. A summary of description of baseline environment and identified dominant air emission sources at the surveyed areas during the site inspection are presented in Table 12.3.

Table 12.3 Baseline Environmental Condition

Area	Baseline Environment
Mai Po	Low density residential area and the surrounding land uses mainly comprise a mixture of open storage, temporary carpark and residential uses. Dominant air emission sources were identified as the traffic emissions from San Tin Highway.
Ngau Tam Mei	Village area with scattered 1- to 2-storey houses.
Tai Kong Po	Village area with the surrounding land uses mainly comprise a mixture of poultry and residential uses.
Shek Kong/Tse Uk Tsuen	Shek Kong PLA Barracks is located next to the SSS and a scattering of residential houses are located in the vicinity.
Pat Heung	Low density residential area. The surrounding land uses mainly comprise a mixture of residential and agricultural uses.
Shek Yam	Well developed urban area. The surrounding major land uses are residential use. Dominant air emission sources are traffic emissions from Kwai Chung Road.
Shing Mun	Well developed urban area. The surrounding land uses are residential use. Dominant air emission source was the traffic emissions from Cheung Pei Shan Road and Shing Mun Road.
Kwai Chung	Well developed urban area. The surrounding land uses are industrial use. Air emission sources were the traffic emissions from Castle Peak Road – Kwai Chung and industrial emissions.
Mei Lai Road	Well developed urban area. The surrounding land uses are educational institutes, residential and recreational uses. Traffic emissions from Ching Cheung Road are dominant air emission source.
Nam Cheong	Well developed urban area. The surrounding land uses mainly comprise a mixture of schools and residential uses. Dominant air emission sources were identified as the traffic emissions from West Kowloon Highway and Sham Mong Road.
Mong Kok West	Well developed urban area. The surrounding land uses mainly comprise a mixture of commercial, GIC and residential uses. Dominant air emission sources were identified as the traffic emissions from West Kowloon Highway, Lai Cheung Road and Ferry Street.
West Kowloon	Well developed urban area. The surrounding land uses mainly comprise a mixture of commercial, GIC and residential uses. Dominant air emission sources were identified as the traffic emissions from West Kowloon Highway, Jordan Road and Canton Road.

12.14 There are six barging points to be proposed for this Project. They would be located at West Kowloon, Nam Cheong, Rambler Channel, Siu Lam, Lung Kwu Sheung Tan and Tsing Chau Tsai. The areas in West Kowloon, Nam Cheong and Rambler Channel are well developed urban areas; while areas in Siu Lam, Lung Kwu Sheung and Tsing Chau Tsai are rural areas.

12.15 Two magazine sites would be proposed to be located at So Kwun Wat and Tai Shu Ha Road West. These areas are considered to be rural areas with low density of population.

12.16 There are currently four Environmental Protection Department (EPD) fixed air quality monitoring stations located within the study area. These monitoring stations are located at Yuen Long, Tsuen Wan, Kwai Chung and Sham Shui Po. The annual averages of pollutants in mg m^-3 monitored at these stations for the Year 2007 are summarized in Table 12.4.

Table 12.4 EPD Air Quality Monitoring Data in 2007

Pollutant	Annual Average Concentration (μg/m^3)
	Yuen Long	Tsuen Wan	Kwai Chung	Sham Shui Po
SO2	24	24	31	20
NO2	55	64	61	69
Ozone	36	29	28	27
TSP	97	79	85	79
RSP	64	59	60	57

Air Sensitive Receivers

12.17 In accordance with Annex 12 of the EIAO-TM, any domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium or performing arts centre are considered as air sensitive receivers (ASRs). Any other premises or place with which, in terms of duration or number of people affected, has a similar sensitivity to the air pollutants as the aforelisted premises and places is also considered to be a sensitive receiver. As stated in the EIA Study Brief, the boundary of the assessment area for air quality assessment should be 500m from the Project alignment and boundaries of all associated areas under the Project. After review of relevant land use plans including the Outline Zoning Plans (OZP) as indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M54/050 - 069, representative ASRs in the proximity of the construction sites (including alignment, terminus, ERS, SSS, access roads, adits, ventilation buildings), temporary stockpiles, concrete batching plants and barging points are identified. These ASRs are considered to be most likely to be affected by the construction of the Project. The representative ASRs are listed in Table 12.5 and their locations are illustrated in Figure No. NOL/ERL/300/C/XRL/ENS/M60/001 – 010, 013 – 024, 026 - 028.

Table 12.5 Representative Air Sensitive Receivers

Works Area	Area ID	ASR	Description	Land Use	Distance between ASR and closest work boundary(m)	No. of storey
Mai Po (Figure No. NOL/ERL/300/C/XRL/ENS/M60/002)
MPV	A	MPA1	House 5 Phase A Royal Palms	Residential (Existing)	57	3
	A	MPA2	Mai Po San Tsuen Village House	Residential (Existing)	5	2
	A	MPA3	No. 166 Mai Po San Tsuen	Residential (Existing)	57	3
	A	MPA4	Proposed Comprehensive Development at Wo Shang Wai (anticipated to be occupied in 2013)	Residential (Planned)	Planned	N/A
Ngau Tam Mei (Figure No. NOL/ERL/300/C/XRL/ENS/M60/003 & 004)
NTV	B	NTA1	Yau Tam Mei Village House	Residential	18	2
	B	NTA2	Yau Tam Mei Village House	Residential	9	2
	B	NTA3	Yau Tam Mei Village House	Residential	9	2
Tai Kong Po (Figure No. NOL/ERL/300/C/XRL/ENS/M60/005, 006 & 007)
TPV	C	TPA1	Kong Tai Road Village House	Residential	8	2
	C (Access Road)	TPA2	Kong Tai Road Village House	Residential	1	1
	C (Access Road)	TPA3	Kong Tai Road No.46	Residential	1	2
	C (Access Road)	TPA4	Kam Hing Wai No.17	Residential	5	3
	C	TPA5	Kong Tai Road Village House	Residential	5	3
	C (Access Road)	TPA6	Oakwood, Seasons Monarch	Residential	11	3
Shek Kong (Figure No. NOL/ERL/300/C/XRL/ENS/M60/008 & 009)
SSS	D	SSA1	630 Sheung Tsuen	Residential	9	2
	D	SSA1a	Nam Hing Lei Village House	Residential	18	3
	D	SSA1b	Nam Hing Lei Village House	Residential	18	1
	D	SSA2	Building 201, Shek Kong Barrack	N/A	16	N/A
	D	SSA3	Leung Uk Tsuen Village House	Residential	6	2
	D	SSA4	Leung Uk Tsuen Village House	Residential	6	2
	D (Access Road)	SSA5	Block 16, Seasons Villas	Residential	1	2
	D	SSA7	Nam Hing Lei Village House	Residential	20	1
	D	SSA8	Leung Uk Tsuen Village House No.32	Residential	51	2
	D	SSA9	DD110 LOT 482, Wang Toi Shan Choi	Residential	3	1
	D	SSA10	No. 265, Kam Tin Road	Residential	9	2
	D	SSA11	Leung Uk Tsuen Squats	Residential	1	2
	D	SSA12	Abandoned village house in Shek Kong	Residential	2	3
Pat Heung (Figure No. NOL/ERL/300/C/XRL/ENS/M60/010)
PHV	F	PHA1	DD 114 LOT 1405 Sheung Tsuen	Residential	2	2
	F	PHA2	No. 305, Sheung Tsuen San Tsuen Village House	Residential	6	4
Tse Uk Tsuen (Figure No. NOL/ERL/300/C/XRL/ENS/M60/010)
TUW	E	TUA1	Tse Uk Tsuen	Residential	6	1
	E	TUA2	No. 489H Tse Uk Tsuen	Residential	12	3
Shek Yam (Figure No. NOL/ERL/300/C/XRL/ENS/M60/013)
SYW	H	SYA1	No. 168, Yau Ma Hom Resite Village	Residential	3	3
	H	SYA2	Sun Fung Centre	Commercial	14	N/A
Shing Mun (Figure No. NOL/ERL/300/C/XRL/ENS/M60/013)
SMV	G	SMA1	Sau Shan House, Cheung Shan Estate	Residential	21	25
	G	SMA2	Cheung Shan Estate Market	G/IC	33	N/A
Kwai Chung (Figure No. NOL/ERL/300/C/XRL/ENS/M60/014)
KCV	J	KCA1	Wah Wing Industrial Building	Industrial	5	N/A
	J	KCA2	Central Kwai Chung Park	Park	6	N/A
	K	KCA3	Drainage Department Maintenance Depot	Industrial	24	N/A
	K	KCA4	Kwai Chung Depot	Industrial	21	N/A
Rambler Channel Barging Point (NOL/ERL/300/C/XRL/ENS/M60/015)
RCB	Z	RBPA1	Kwai Chung Preliminary Treatment Works	Industrial	9	N/A
Mei Lai Road (Figure No. NOL/ERL/300/C/XRL/ENS/M60/016)
MLW	L	MLA	Po Leung Kuk Tong Nai Kan College	School	2	7
Nam Cheong including barging point (Figure No. NOL/ERL/300/C/XRL/ENS/M60/016 to 018)
NCV	S	NCA1	West Kowloon Disciplined Services Quarters Block 1	Residential	6	38
	S & T	NCA2	Tower 6, Harbour Green	Residential	6	45
	S & T	NCA3	Nam Cheong Park	Recreational	7	N/A
	R	NCA4	Cheong Yat House, Nam Cheong Estate	Residential	38	15
	O	NCA5	Fu Hoi House, Fu Cheong Estate	Residential	12	19
	P	NCA6	Tack Ching Girls' Secondary School	School	9	8
	P	NCA7	St. Margaret's Co-educational English Secondary & Primary School	School	42	8
	Y (Barging Point)	NCA8	New World First Ferry	Industrial	6	1
	M	NCA9	Workshop next to Yuet Lun Street	Industrial	27	N/A
	M	NCA10	William Chandler Factory Building	Industrial	87	N/A
	S	NCA11	Tower 1, Metro Harbour View	Residential	24	45
Mong Kok West (Figure No. NOL/ERL/300/C/XRL/ENS/M60/019)
MKV	U & V	MKA1	Yaumati Catholic Primary School (Hoi Wang Road)	School	27	8
	U & V	MKA2	Hong Kong Community College - West Kowloon Campus	School	36	16
West Kowloon including barging point (Figure No. NOL/ERL/300/C/XRL/ENS/M60/020 & 021)
WKT	V	WKA1	FSD West Kowloon Rescue Training Centre	Institutional	16	N/A
	V	WKA2	Planned Residential Development at Hoi Wang Road	Residential (Planned)	Planned	N/A
	V	WKA3	Sorrento Tower 6	Residential	5	52
	W	WKA5	Tsim Sha Tsui Fire Station	G/IC	8	N/A
	W	WKA6	The Arch Sky Tower	Residential	9	54
	W	WKA7	The Arch Moon Tower	Residential	6	53
	W	WKA8	The Waterfront, Tower 3	Residential	5	38
	V	WKA9	46-48 Man King Building	Residential	10	19
Siu Lam Barging Point (Figure No. NOL/ERL/300/C/XRL/ENS/M60/022)
SLB	AA	SLBA1	Lok On Pai Siu Lam Flea Market	Commercial	21	N/A
	AA	SLBA2	Aqua Blue Block 3	Residential	99	6
Magazine Site next to Tai Shu Ha Road West (Figure No. NOL/ERL/300/C/XRL/ENS/M60/023)
TSW	AE	TSA1	Village House next to Tai Shu Ha Road West	Residential	54	1
Magazine Site at So Kwun Wat (Figure No. NOL/ERL/300/C/XRL/ENS/M60/024)
SKW	AC	SKW	Grandview Terrace	Residential	27	2
Tsing Chau Tsai Barging Point (Figure No. NOL/ERL/300/C/XRL/ENS/M60/026)
TCB	AG	TCA1	Lantau Toll Plaza Administration Building	Commercial	273	2
	AG	TCA2	Shipyard at Tsing Chau Tsai	Industrial	82	N/A
Siu Lang Shui Storage and Plant Nursery Area (Figure No. NOL/ERL/300/C/XRL/ENS/M60/027)
SLSW	AB	TMA1	Planned Sensitive Use at the Former Siu Lang Shui Landfill	Camp Site/Education Use	57	N/A
Lung Kwu Sheung Tan Barging Point (Figure No. NOL/ERL/300/C/XRL/ENS/M60/028)
LKB	AF	LKA1	Office of Concrete Plant	Industrial	23	1

Potential Sources of Impact

Construction Phase

12.18 The Hong Kong section of the XRL is approximately 26km from new terminus located in WKT to the boundary of Hong Kong. Except for the construction of the railway alignment, the Project includes eight ventilation buildings, three ventilation adits at Pat Heung, Shing Mun and Kwai Chung, eight construction shafts (of which will be occupied by future ventilation buildings), Tai Kong Po Emergency Access Point (TPP), an Emergency Rescue Station (ERS) at Shek Kong and Shek Kong Stabling Sidings (SSS). In addition, there are six barging points located at West Kowloon, Nam Cheong, Rambler Channel, Siu Lam, Lung Kwu Sheung Tan and Tsing Chau Tsai, one concrete batching plant at West Kowloon, and two temporary magazine sites at Tai Shu Ha Road West and So Kwun Wat.

12.19 Major construction works/activities that would contribute to construction dust impacts would include surface works for the construction of the superstructures including the eight ventilation buildings and West Kowloon Terminus, TPP, SSS, ERS, a PTI and a substation nearby WKT, the Project alignment by cut-and-cover technique, operation of a concrete batching plant and barging points. The standard working hours will be from 0700 to 1900 hours from Monday to Saturday excluding public holidays. Locations of the cut and cover work sites, ventilation buildings, ERS, SSS, temporary stockpiles, temporary magazine sites, concrete batching plant and barging points are illustrated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/001 - 010, 013 – 024, 026 - 028. The details of construction activities and potential emission sources are described as follows.

Tunnel, Adits & Shafts, Ventilation Buildings/EAP

12.20 The construction for tunnel would involve cut and cover, drill and blast, and soft ground TBMs. The drill and blast and TBM would be performed entirely underground, therefore, potential dust impacts could be expected from the section of alignment using the cut and cover technique. Dusty construction activities would include excavation, material handlings and transportation of spoils on the paved haul road within the site.

12.21 The tunnel sections using cut and cover technique would be at Shek Kong works area (location of ERS and ramp structure), Nam Cheong works area and West Kowloon works area (including WKT). Potential dust impact would be expected at the ASRs in the vicinity of these works areas. Table 12.6 summarizes the sections constructed by cut-and-cover method.

Table 12.6 Tunnel Construction using Cut and Cover Method

Area ID	Chainage *		Length	Type
	From	To	(m)
D	123+540	124+315	775	ERS Cut & Cover
D	124+315	124+912	597	Cut & Cover ramp structure
Q	140+380	140+540	160	Nam Cheong Cut & Cover
U	140+570	140+800	230	Mong Kok West Cut & Cover
W & V	140+800	141+684	884	West Kowloon Terminus Cut & Cover Station Box

Note: * Chainage refer to Figure No. NOL/ERL/300/C/XRL/ENS/M53/207 to /208 and /221 to /228.

12.22 There are adits and shafts to be built along the Project alignment for the operational tunnel ventilation and are also used during construction phase. These provide access for tunnelling equipment, permanent material and the removal of spoil (for sections of Project alignment using TBM and drill and blast method). A summary of the construction shafts and adits is presented in Table 12.7.

Table 12.7 Locations of Construction Shafts and Adits

Location	Area ID	Principle Activity	Future Use	Length (m)	Width (m)
Mai Po Shaft	A	Launching and retrieval of TBM	Mai Po Ventilation Building	204	57
Ngau Tam Mei Shaft	B	Retrieval of TBM & drive drill and blast tunnel	Ngau Tam Mei Ventilation Building	130	25
Tai Kong Po Shaft	C	Retrieval of TBM & drive drill and blast tunnel	Tai Kong Po Emergency Access Point	60	55
ERS - North Access	D	Launching of TBM, ERS construction	-	840	27
ERS Ramp	D	Launching of TBM	-	595	27
Tse Uk Tsuen Shaft	E	Retrieval of TBM	-	12	30
Pat Heung Adit	F	Drive drill and blast tunnel south	Pat Heung Ventilation Building	20	12
Shing Mun Shaft	G	Shaft construction	Shing Mun Ventilation Building	16	16
Shek Yam Adit	H	Drive drill and blast tunnel north & south	-	10	16
Kwai Chung Adit	J	Drive drill and blast tunnel north & south	Kwai Chung Ventilation Building	25	12
Mei Lai Road Shaft	L	Drive dill and blast tunnel north & retrieval of TBM	-	18	18
Nam Cheong Shaft	P	Launching of TBMs north and south	Nam Cheong Ventilation Building	214	30
Hoi Ting Road Shaft	V	Retrieval of TBM	-	30	18
Mong Kok West Shaft	V	-	Mong Kok West Ventilation Building	35	22

12.23 The size of the construction area for each adit/shaft would be limited. After site clearance and open-cut excavation at the surface area, the sheet piles/diaphragm wall would be installed. Generally, the tracked crane would be used for mucking out. The mucking areas would not be fully enclosed. However, during excavation and unloading of spoils, water spraying would be provided to alleviate potential dust emissions. All the trucks loaded with spoil would be well covered by impervious cover before leaving the mucking-out areas. Therefore, adverse dust impact from the transportation of spoil would not be anticipated.

12.24 Regarding the Mei Lai Road Shaft, an overhead gantry crane would be constructed. An enclosed spoil removal hoist (with bucket hopper) would be provided for mucking out as the ASRs just located next to the shaft. The excavation work would be carried out in enclosed area and the excavation level would be from ground level to underground level. The spoil removal process would also be conducted inside the enclosed structure. There is a dust extraction system equipped with the filters serving this enclosed structure. As same as other adits/shafts, all the trucks loaded with spoil must be well covered by impervious cover before leaving the mucking-out area. No adverse dust impact from the transportation of spoil would be anticipated.

12.25 Wheel watering facilities would be provided at every designated vehicle exit point of construction areas. Since all vehicles would be washed at exit points and all trucks loaded with the dusty materials would be covered entirely before leaving the construction sites, the dust nuisance from construction vehicle movement outside the work site is unlikely to be significant. The access roads to the adits/shafts at rural areas are normally existing local roads. As the width of some local roads may be not enough for the trucks travelling, minor widening of local roads would be carried out before the mucking out activities. In view of minor road improvement works and implementation of the dust suppression measures, adverse dust impact would not be anticipated during widening of local access roads.

12.26 A temporary stockpile area would be located adjacent to each shaft/adit and the area would be about 30m x 20m (enough for 24 hours only). All excavated spoil would be transported from the mucking-out area to the barging point per day. If the operation of the barging point is ceased, the spoil materials would be stored in the temporary stockpile. Impervious sheeting would be well covered on it and water spraying system would also be installed to minimize dust emissions. Adverse dust impacts are not anticipated.

12.27 A building for EAP and a total of eight ventilation buildings along the Project alignment will be provided. The buildings will all sit on top of a shaft or adjacent to an adit which will be in use to support the tunnel construction. The buildings are simple reinforced concrete structures with rooms to house the ventilation fans and support systems. Minor improvement works on the access roads to the ventilation buildings would also be undertaken under the Project. Adverse dust impacts arsing from construction of these buildings and minor road improvement works are not anticipated with the implementation of dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation.

West Kowloon Terminus

12.28 The construction activities for West Kowloon Terminus (WKT) would include site clearance, excavation, foundation works and superstructure construction. A stockpile would be located next to the WKT site for temporary storage of the excavated spoils. The active area of this stockpile would be limited to 15% of the total area. Since the West Kowloon Terminus would be constructed concurrently with the construction of Project alignment, operation of concrete batching plant and barging points, cumulative dust impacts would be expected.

ERS at Shek Kong and Shek Kong Stabling Sidings

12.29 The ERS and associated ramp would be constructed using cut and cover technique. The construction methods would be a temporary diaphragm wall around the permanent insitu box structure. Potential dust impacts from the construction of the ERS would be anticipated. The stabling sidings will be located at grade on the west of the ERS box. As it would involve minor excavation works, adverse dust impacts would not be expected with the implementation of dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation.

Barging Points

12.30 There are six new barging points to be provided for this Project. They would be located at West Kowloon, Nam Cheong, Rambler Channel, Siu Lam, Lung Kwu Sheung Tan and Tsing Chau Tsai. The schematic diagram for barging points is attached in Appendix 12-1. All barging points will operate for 12 hours a day (7:00 to 19:00) except Sunday and public holidays and the typhoon No.3 or above hoist. The spoil materials would be directly transported to the tipping halls of the barging points by trucks and then unload to the barges. A stockpile area would be provided adjacent to the each barging point which serves a temporary store area for excavated spoils if the barge is not available for unloading. As confirmed with the Project Proponent, the active area of this temporary stockpile area would be limited to 30% of the total area. The other inactive area would be well covered with impervious sheeting. Water spraying system would be applied to the active area.

12.31 The haul roads within the barging sites would be all paved and water spraying would be provided on the haul roads to keep wet condition. Vehicles would be required to pass through designated wheel washing facilities before leaving the barging facilities. To alleviate the potential dust impacts, the dusty materials on the trucks would be well covered. The tipping halls would be three sides enclosure with a top cover, water spraying and dust curtain would be provided at the loading points (from barging point to the barges).

12.32 The details of each barging point and potential impact are described as follows.

West Kowloon Barging Point

12.33 The barging facilities would include two loading ramps (at the approximate locations of KSL barging points) and three no. additional new ramps at the west (See Figure No. NOL/ERL/300/C/XRL/ENS/M50/008). The transportation of excavated spoils would be carried out by trucks from the work face (or stockpiling area) to the barging points. The maximum number of trucks per day is estimated to be 900. There are other dusty activities such as materials handling at the stockpiles, operations of concrete batching plant and construction of West Kowloon Terminus would be conducted concurrently adjacent to this barging point, cumulative dust impact would be expected at the nearby ASRs.

Nam Cheong Barging Point

12.34 The barging facilities would have three ramps (See Figure No. NOL/ERL/300/C/
XRL/ENS/M50/007). The barging point at Nam Cheong is approximately 450m from Nam Cheong Shaft which will be used for mucking out of soft ground TMB Tunnel drives and the associated launch shaft. The transportation of excavated spoils would be carried out by a combination of trucks or conveyor system from the work face (or stockpiling area) to the barging points. A conveyor system would be provided to transport the excavated materials to one barging point. As it is an enclosed conveyor belt, dust impacts arising from the transportation of the excavated materials through conveyor system are not expected. However, transportation of excavated materials by trucks would be deployed for the other two barging points. There are other dusty activities such as materials handling at the temporary stockpile. If the barges are not operated, the excavated materials from the conveyor/trucks would be temporarily stored on this stockpile as emergency. Open-cut excavation for Project alignments would also be conducted simultaneously adjacent to this barging point, cumulative dust impact would be expected at the nearby ASRs.

Rambler Channel Barging Point

12.35 The barging facilities would include two ramps (see Figure No. NOL/ERL/300/C/XRL/
ENS/M50/009). The construction activities within this works area would be limited to material handling at the temporary stockpiles and unloading spoils to the barges. There is only one identified ASR (office of Kwai Chung Preliminary Treatment Works) within the study area (see Figure No. NOL/ERL/300/C/XRL/ENS/M60/015). No other dusty activities would be undertaken within the study area concurrently. With the implementation of measures as mentioned in Sections 12.30 and 12.31, no adverse dust impact arising from the operation of this barging point is anticipated.

Siu Lam Barging Point

12.36 The barging facilities would include two ramps (see Figure No. NOL/ERL/300/C/XRL/
ENS/M50/010). The construction activities within this works area would be limited to material handling at the temporary stockpiles and unloading spoils to the barges. Other dusty activities would not be undertaken concurrently within the study area. With the implementation of measures as mentioned in Sections 12.30 and 12.31, no adverse dust impact arising from the operation of this barging point is expected.

Lung Kwu Sheung Tan Barging Point and Tsing Chau Tsai Barging Point

12.37 Each of these two barging points would include two ramps (see Figure No. NOL/ERL/300/C/XRL/
ENS/M50/014 and NOL/ERL/300/C/XRL/ENS/M50/015). The construction activities within these works areas would be limited to material handling at the temporary stockpiles and unloading spoils to the barges. Other construction activities would not be undertaken concurrently within the study areas. With the implementation of measures as mentioned in Sections 12.30 and 12.31, dust impact arising from the operation of these two barging points are not expected.

Concrete Batching Plant

12.38 A concrete batching plant would be located at West Kowloon works area and the layout plan is shown in Appendix 12-1. The plant will have a daily maximum production rate of 3,000 m³ and will operate for 12 hours a day (7:00 to 19:00) except Sundays and public holidays. Major plant components include one receiving hopper for aggregate, one receiving hopper for cement, enclosed aggregate conveying system, air slide for large capacity cement silo, an aggregate storage bin, two large capacity cement silos (total capacity of 4,000 tonnes) with dust collectors, nine enclosed cement/PFA silo (capacity of 100 tonnes per silo) and three mixing towers with dust collectors. A wastewater treatment area would be provided to collect returned concrete and wash out water generated from batching plant operations and then reuse or dumping to the landfill after treatment.

12.39 The aggregate would be transported through both marine and land access by barge and tipper trucks, respectively. The aggregates would be unloaded onto the receiving hopper (for both land and marine access) provided with enclosures on three sides in addition to top cover and equipped with water spraying system. The conveyor belt underneath the receiving hopper would transfer the aggregates to the proper compartment of the overhead storage bins of the batching plant.

12.40 The cement would also be transported through both marine and land access by barge and cement tankers respectively. The cement by barge would be unloaded onto the receiving hopper and then transfer to the two large capacity cement silos via air slide. On the land access, cement tanker and PFA tanker would be towed by tractors to the plant site. The tractors would be equipped with a blower for blowing cement or PFA via flexible duct directly from the tanker into the nine small cement/PFA silos (3 cement silos and 6 PFA silos) of the concrete batching plant. Each silo would have a level sensor to monitor and control the refilling level of cement/PFA. Once the material has reached the designated level, the alarming system, with ringing sound and flashing light, would be activated to draw the attention of responsible operator to stop the pumping process manually.

12.41 The size of aggregates bins and cement silo are sufficient to ensure concrete production, therefore, there is no storage area within the site. The aggregate and cement conveying systems are fully enclosed.

12.42 Aggregates would be transferred to the weighting hopper via a chute from their overhead storage bins. Cement/PFA would be loaded into the weighting hopper via a crew conveyor from their respective silo. Admixture and water would be supplied to their respective weighting hopper via pipes linking the supply sources and the weighing hoppers. Each batch of raw materials would be weighed on the weighing hoppers of the batching plant before discharging into the mixer for thorough mixing. The whole process of weighing and mixing is performed in a totally enclosed environment (i.e. Mixing Tower 1, 2 and 3). After completion of the mixing process, the concrete would be discharged from the mixer into the transit mixer of a truck.

12.43 The maximum consumption rate of raw materials per day would be 1,200 tonnes of cement, 450 tonne of PFA and 6,000 tonnes of aggregate. One dust collector is assumed to serve for each silo/mixer, therefore, fourteen dust collectors in total would be employed in the concrete batching plant. The filter capacity of dust collectors for large capacity cement silo and small silo/mixer would be 3,528 m³/hour and 1,780 m³/hour, respectively. The design emission concentrations of the dust collectors for large capacity cement silo, mixer and small silos for cement/PFA would be limited to not more than 50mg/m³; 40mg/m³ and 30mg/m³. The area within the plant would be paved and water spraying would be provided on the haul roads to keep wet condition. Vehicle washing facility would be provided at the gate for wheel washing before leaving the plant.

12.44 The potential dust emissions sources of the concrete batching plant would be unloading of aggregate on the receiving hoppers, haul road within the plant and dust collectors on the top of large capacity cement silos, cement/PFA silos and mixers.

Temporary Magazine Sites

12.45 The construction of the Project would involve substantial amount of rock excavation of which majority could be carried out by drill and blast method. Two temporary magazine sites are proposed to be constructed at the areas in the vicinity of Tai Shu Ha Road West and So Kwun Wat, to support the construction of XRL. All magazine sites are located above ground level. Very minor excavation works and superstructure works would be conducted for the construction of the magazine storage buildings in the initial stage of the construction programme. Water spraying and the dust control measures as stated in the Air Pollution Control (Construction Dust) Regulation would be applied. In view of limited site areas and implementation of dust suppression measures, no adverse dust impact would be expected during construction of magazine storage buildings. Once the magazine storage buildings are constructed, the major activities would be the vehicles entering/leaving the magazine sites. Insignificant dust impacts from the operation of the magazine sites are anticipated as the roads to/from and within the magazine site will be paved.

Cumulative Dust Impacts from Other Concurrent Projects

12.46 The construction works would commence in December 2009 and the overall project completion is anticipated to be in 2015. As discussed in Section 2, the Project is likely interactions with the some projects (excluding Central Kowloon Route and West Kowloon Cultural District as the programme is not yet confirmed at the time of assessment). However, cumulative adverse dust impact would not be expected as the impact of other concurrent projects is localized or the major dusty activities would not be undertaken concurrently.

Table 12.8 Interfacing Project

Interfacing Project	Construction Period	Nearby Work Site	Possible cumulative adverse dust impacts
Road Works at West Kowloon	2012 to 2014	West Kowloon Works area	The maximum operation rate of all construction activities and the largest size of the construction work sites for XRL would occur in 2010.  In the 3rd quarter of 2011, the area of the cut and cover work site at West Kowloon works area has been decreased significantly and the handling capacity of the barging point would also decrease comparing with the scenario in 2010.  The excavation at WKT would also be completed in December 2011.  The dust impact arising from the Project “Road Works at West Kowloon” is expected to be localized.  Therefore, no adverse cumulative dust impacts would be expected.
Construction of Cycle Tracks and the associated Supporting Facilities from Sha Po Tsuen to Shek Sheung River	Mid 2009 to Early 2012	Mai Po Shaft	No. Insignificant dust impact from construction of cycle tracks and associated supporting facilities is expected as mentioned in the approved EIA Report.
Proposed Comprehensive Development at Wo Shang Wai, Yuen Long	2008 to 2012	Mai Po Shaft	No. As mentioned in respective approved EIA Report, the potential air quality impact is anticipated to be short-term and can be controlled at acceptable levels through appropriate design and good site practice stipulated in the Air Pollution Control (Construction Dust) Regulation.
Upgrading of Remaining Sections of Kam Tin Road and Lam Kam Road	2010 to 2014	Shek Kong Stabling Sidings	No. Localized dust impact from upgrading works of Kam Tin Road and Lam Kam Road.
Yuen Long & Kam Tin Sewerage and Sewage Disposal	2009 to 2013	Mai Po Shaft and Shek Kong Stabling Sidings	No. Dust impact would be localized.

Operation Phase

12.47 During operation of the Project, no air pollutants emissions would be generated from the electrical railway. The only source of carbon dioxide (CO₂) would be from the breathing of the passengers and staff working in the station. The ventilation system is designed for an air exchange rate of 5 litre/person/second in accordance with MTRC Design Manual. As a result, all CO₂ exhaled by passengers/staff would be sufficiently diluted by the fresh air intake before being discharged through the normal air exchange. Similar to other electrified rail projects with substantial sections underground (e.g. Kowloon Southern Link), air quality impact from the operations of vent shafts would not be considered a key environmental issue.

12.48 The vent shaft is also designed to be sited at more than 5m from any opening at the adjacent building, in accordance with the Fire Services Department’s requirement. According to the preliminary design of Project, the distance between the vent shafts and openings of the adjacent building would be over 8m away, and at this distance, there should be no noticeable temperature effect as a result of emissions from vent shafts. The vent shafts would therefore not expect to lead to adverse air quality impacts to the neighbourhood. It is noted that the separation distance between the Ngau Tam Mei Ventilation Building and the Ngau Tam Mei Composting Plant would be about 200m. The compositing plant is equipped with stringent controls on odour, and therefore the potential odour impact on the ventilation building would be insignificant during operation phase.

12.49 In accordance with the preliminary design, maximum of six diesel or electrical locomotives will be provided at SSS. Potential air pollutants emitted from the diesel locomotive would include nitrogen dioxide, sulphur dioxide and particulates. However, the potential air quality is expected to be insignificant as it is in occasional operation and only one diesel locomotive to be operated at one time.

12.50 The potential air quality impact on PTI at the Ventilation Building Complex (next to West Kowloon Terminus) would be traffic emissions from travelling and idling vehicles. To alleviate the adverse air quality impacts, mechanical air ventilation would be provided to the PTI. The design of the ventilation system would fulfil the air quality guideline of PTI stipulated in EPD’s ProPECC PN1/98 Control of Air Pollution in Semi-confined Public Transport Interchanges. No adverse air quality in the PTI would be anticipated.

Assessment Methodology

Construction Phase

12.51 Referring to Sections 12.11 – 12.46, potential adverse dust impact would be expected from open-cut excavation for some sections of Project alignment at Shek Kong, Nam Cheong and West Kowloon Terminus, construction of ERS at Shek Kong, and operation of concrete batching plant at West Kowloon works area. Quantitative assessment is therefore conducted for the works areas (including the stockpiles and adits/shafts) at West Kowloon, Nam Cheong and Shek Kong.

12.52 Regarding construction of adits/shafts/ventilation buildings/EAP at other areas, loading and unloading of spoils at the adits/shafts and nearby stockpiles, minor excavation for SSS and operation of magazine sites, no adverse dust impact at nearby sensitive receivers would be expected due to limited dusty construction activities and minor excavation works. With the implementation of dust suppression measures as stipulated in Air Pollution Control (Construction Dust) Regulation, no adverse dust impacts would be expected from these construction activities. Therefore, the potential dust impacts arising from these works areas are addressed qualitatively in the study, except that the stockpiles at Pat Heung Adit and Tse Uk Tsuen Shaft which would be located within 500m of Shek Kong works area to be considered in the cumulative air quality assessment.

12.53 Limited dust impact from unloading of spoils at the barging points would be expected as the tipping hall is provided with enclosures on three sides and top cover. In addition, the mitigation measures such as water spraying system and dust curtain provided at the loading point, well covered the inactive temporary stockpiles areas, and water spraying on the active stockpiles area and haul roads would also be applied. However, the barging points at West Kowloon works area and Nam Cheong works area would operate concurrently with the other dusty construction activities within 500m study area. Quantitative assessments for the barging points at West Kowloon works area and Nam Cheong works area are conducted to determine the cumulative dust impacts on the nearby ASRs. Qualitative assessment approach is adopted for the operation of barging points at Rambler Channel works area, Siu Lam works area, Lung Kwu Sheung Tan works area and Tsing Chau Tsai works area.

Emission Inventory

12.54 Predicted dust emissions are based on emission factors from USEPA Compilation of Air Pollution Emission Factors (AP-42), 5th Edition. The scenario under the peak rate of all construction activities and the largest size of works sites are considered in the assessment. The major dusty construction activities for the Project to be considered in the modelling assessment include:

(A) West Kowloon Works Area

(i) Barging Point (5 ramps)

- Transportation of the spoils to the enclosed tipping hall of Barging Point by trucks on the paved haul road

- Unloading point to the barge

(ii) Tunnel Cut & Cover areas and West Kowloon Terminus

- Heavy construction activities including excavation and material handlings within the construction site

- Wind erosion of open active site

- Materials handling and wind erosion at the active stockpile

-

(iii) Concrete Batching Plant

- Unloading of aggregates to the receiving hopper

- Emissions from dust collectors on the top of large capacity cement silos, cement/PFA silos and mixers

- Transporting of raw materials/products by trucks on the paved haul road within the plant

(B) Nam Cheong Works Area

(i) Barging Point (3 ramps)

- Transportation of the spoils to the enclosed tipping hall of Barging Point (2 ramps) by trucks on the paved haul road

- Unloading point to the barge

- Materials handling and wind erosion at the active temporary stockpile (emergency use)

(ii) Tunnel Cut & Cover areas and vent shaft

- Heavy construction activities including excavation and material handlings within the construction site

- Wind erosion of open active site

- Materials handling and wind erosion at the active stockpile

(C) Shek Kong Works Area

(i) Tunnel Cut & Cover areas and vent shaft

- Heavy construction activities including excavation and material handlings within the construction site

- Wind erosion of open active site

(ii) ERS site

- Heavy construction activities including excavation, stockpile handling works and slope works within the construction site

- Emissions from trucks travelling on paved haul roads

- Wind erosion of open active site

12.55 According to the preliminary engineering design information, the maximum production capacity of the concrete batching plant would be 3,000 m³ per day. The total capacity of silo exceeds 50 tonnes and in which cement is handled. The operation of the concrete batching plant is therefore classified as Specified Process (SP). The Contractor should apply the SP license under APCO. The requirements and mitigation measures stipulated in the Guidance Note on the Best Practicable Means for Cement Works (Concrete Batching Plant) BPM 3/2(93) should be followed and implemented. The dust control measures have been incorporated into the design of the concrete batching plant, barging facilities and stockpile areas, as presented in Tables 12.9, 12.10 and 12.11, respectively. The schematic diagrams for the barging points with the dust emission control measures are presented in Appendix 12-1. These dust control measures have also been taking into account in the assessment.

Table 12.9 Concrete Batching Plant – Dust Emission Design Control Measures

Process	Description	Dust Emission Design Control Measures
Unloading of raw materials	Unloading of aggregates from the tipper trucks to receiving hopper.	The aggregates would be unloaded from the tipper trucks to the receiving hopper equipped with enclosures on 3 sides and top cover, and water spraying system. As a worst case scenario, minimal dust emission would be generated during unloading the raw materials.
	Unloading of cement and PFA from tankers into the silo.	The cement and PFA would be directly loaded into the silo via a flexible duct. Dust collectors would be installed at cement/PFA silos, therefore, no dust emission would be expected.
Transfer of raw materials	Storage of aggregates in overhead storage bins.	The aggregates would be stored in fully enclosed overhead storage bins. The top of overhead storage bins would be covered with cladding. Water spraying system would be installed at the top of storage bins for watering the aggregates, and aggregate storage bins would be fully enclosed. Thus, no dust emission would be expected.
Batching of raw materials	Weighing and Batching of cementitious materials	The whole process of weighing and mixing would be performed in a fully enclosed environment. The mixers would all equip with dust collectors, no dust emission would be expected.
Truck loading	Loading of concrete from mixer into transit mixer of a truck	The concrete would be directly loaded from the mixer into the transit mixer of a truck in “wet” form, no dust would be generated in this process.
Trucks	Tipper trucks and cement tankers within the site.	Haul road within the site is paved. Wheel washing pit would be installed at the gate of the concrete batching plant. Insignificant dust emission generated from the paved haul road would be expected. Water spraying system would be installed along the haul road.

Table 12.10 Cut & Cover Area and Stockpiles – Dust Emission Design Control Measures

Process	Description	Dust Emission Design Control Measures
Cut & Cover Areas and Stockpiles in the vicinity of adits/shafts
Heavy construction activities at Cut & Cover Areas, Storage of materials at Stockpiles	Active areas for heavy construction activities, loading & unloading materials at stockpiles	The specified requirements for cut & cover areas and stockpiles at Shek Kong, Nam Cheong and West Kowloon works areas are as follows: (i) Shek Kong works area – active area minimized to 15% of total area, watering with complete coverage of active area ten times a day. (ii) Nam Cheong works area – active area minimized to 30% of total area, watering with complete coverage of active stockpile area four times a day. (iii) West Kowloon works area – active area minimized to 15% of total area, watering with complete coverage of active area eight times a day. For other sites, the active area would be minimized to 30% of the total area, water spraying system would be applied on the active area and watering with complete coverage of active area four times a day would be required. The remaining inactive area would be well covered with impervious sheeting at all work sites.
Trucks	Transportation of materials	Wheel wash facilities provided at the site exit. The vehicles would be washed before leaving the stockpiles. The spoils would also be well covered before leaving the site in order to minimise generation of dusty materials. The haul roads within the site would be all paved and water spraying would be provided to keep the wet condition. For the Shek Kong works area, watering paved haul roads once per hour would be provided.
Temporary stockpiles in the vicinity of barging points
Loading point	Loading of spoils from trucks onto stockpile	Water spraying would be provided at the loading points to suppress the dust impact.
Storage of materials	Active area for loading & unloading materials	Water spraying system would be applied on the active area and watering with complete coverage of active area four times a day would be required.

Table 12.11 Barging Facilities – Dust Emission Design Control Measures

Process	Description	Dust Emission Design Control Measures
Haul road within barging facilities	Transportation of spoils to the Barging Point	All road surfaces within the barging facilities would be paved and water spraying would be provided to keep the wet condition. For haul roads at West Kowloon and Nam Cheong works areas to the barging points, watering haul road once per hour would be provided.
Unloading of materials	Unloading of spoil materials to the barge	The unloading process would be undertaken within enclosed tipping hall. Water spraying and dust curtain would be provided at the discharge point for dust suppression.
Trucks	Vehicles leaving the barging facility	Vehicle wheel washing facilities provided at site exit.
Transportation of spoils (only for one of Nam Cheong Barging Point)	Transportation of spoils to Nam Cheong Barging Point	Fully enclosed conveyor system would be adopted for transportation of spoils from shaft to the barging point.

12.56 The excavation rate, material handling rate, moisture content, silt content, number of trucks and truck speed are based on the preliminary engineering design. The emission rate of identified pollutant sources in the West Kowloon works area, Nam Cheong works area and Shek Kong works area are summarised in Tables 12.12, 12.13 and 12.14, respectively. Detailed calculations of the emission factors and locations of potential dust emission sources are given in Appendix 12-1 and NOL/ERL/300/C/XRL/ENS/M60/301 to 306.

Table 12.12 Emission Factors for Dusty Construction Activities at West Kowloon Works Area

Emission Source	Activity	Emission Rate	Remarks
Concrete Batching Plant	Unloading of aggregates to the receiving hopper of concrete batching plant	E =0.0035 kg/Mg = 2.43056 x 10^-^2 g/s	AP42 Section 11.12, (aggregate transfer) Max. loading rate of aggregate = 500 tons/hr 95% reduction for the unloading in the tipping hall with enclosures on three sides in addition to top cover, and equipped with water spraying system
	Dust collector for each small Cement Silo	E =30mg/m^3 =1.48333 x 10^-^2 g/s	Design emission concentration of 30 mg/m^3 Exhaust Rate for dust collector: 1780m^3/hr Number of small Cement Silos: 3
	Dust collector for each Large Capacity Cement Silo	E =50mg/m^3 =4.90000x 10^-^2 g/s	EPD BPM for Cement Works (Concrete Batching Plant) emission limits: 50mg/m^3 Exhaust Rate for dust collector: 3528m^3/hr Number of Large Capacity Cement Silos: 2
	Dust collector for each PFA Silo	E =30mg/m^3 =1.48333 x 10^-^2 g/s	Design emission concentration of 30 mg/m^3 Exhaust Rate for dust collector: 1780m^3/hr Number of PFA Silos: 6
	Dust collector for each Mixer	E =40mg/m^3 =1.97778x 10^-^2 g/s	Design emission concentration of 40 mg/m^3 Exhaust Rate for dust collector: 1780m^3/hr Number of Mixer: 3
	Paved Haul Road within Concrete Batching Plant	E = 1424 g/VKT =6.92456 x 10^-^4 g/m/s	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12g/m^2 Averaged truck weight: 21 tons No. of truck trips: 420 truck trips/day, 95% reduction by water spraying to keep wet condition on paved haul road and wheel washing pit installed at the gate of the concrete batching plant. AP42, Section 13.2.1.
Cut and Cover Locations and stockpile area at West Kowloon Works Area	Cut and Cover Area and Stockpile	E=2.69 Mg/hectare /month of activity =3.89178 x 10^-6 g/m^2/s	15% area actively operating 87.5% reduction by complete watering coverage of active construction area eight times a day AP42, Section 13.2.3
	Wind Erosion (night time)	E=0.85Mg/hectare /year =4.043 x 10^-^7 g/m^2/s	15% active site AP42, Table 11.9.4
Barging Point at West Kowloon Works Area	Unloading of spoils to barge at West Kowloon Terminus Works Area	E=3.54 x 10^-^4kg/Mg = 4.26664 x 10^-^3 g/s	E= k x (0.0016) x [(U/2.2)^1.3 / (M/2)^1.4] AP42, Section 13.2.4 AP-42, S13.2.4, particle size < 30 um, 1/95 ed Material Moisture Content (M) : 5% Max. handling capacity for each barging point: 434Mg/hr Number of barging points at West Kowloon Works Area: 5 Unloading within the tipping hall with enclosures on three sides in addition to a top cover, water spray and flexible dust curtain will be provided at discharging point. 90% reduction of dust emission assumed.
	Paved haul road -Transport the spoil from the stockpile to the Barging Point (The paved haul road served for 5 ramps, therefore, number of trucks on each section of the haul road would be different. Details refer to Appendix 12.1)	E = 947 g/VKT =1.97363 x 10^-^4 g/m/s (for 360 truck trips) =3.94727 x 10^-4 g/m/s (for 720 truck trips) =4.93408 x 10^-^4 g/m/s (for 900 truck trips) =5.92090 x 10^-^4 g/m/s (for 1080 truck trips) =7.89453 x 10^-^4 g/m/s (for 1440 truck trips) =9.86817 x 10^-^4 g/m/s (for 1800 truck trips)	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12 g/m^2 Averaged truck weight: 16 tons No. of truck trips: 360 to 1800 truck trips/day 97.5% reduction by watering haul road once per hour and keeping paved haul roads in wet condition. AP42, Section 13.2.1.

Table 12.13 Emission Factors for Dusty Construction Activities at Nam Cheong Works Area

Emission Source	Activity	Emission Rate	Remarks
Construction Site for cut-cover section of Project Alignment and ventilation building	Heavy Construction Activities and Stockpile Areas	E=2.69 Mg/hectare /month of activity =1.55671 x 10^-5 g/m^2/s	30% area actively operating 75% reduction by complete watering coverage of active construction area four times a day AP42, Section 13.2.3
	Wind Erosion (night time)	E=0.85Mg/hectare /year =8.08600 x 10^-^7 g/m^2/s	30% active site AP42, Table 11.9.4
	Paved Haul Road within site	E = 947 g/VKT =6.31563 x 10^-4 g/m/s	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12 g/m^2 Averaged truck weight: 16 tons No. of truck trips: 288 truck trips/day 90% reduction by water spraying to keep wet condition on paved haul roads AP42, Section 13.2.1
Barging point at Nam Cheong Works Area	Unloading of spoils from conveyor / trucks to barge for Nam Cheong Works Area	E =1.28x10^-^3kg/Mg = 1.67442 X 10^-2 g/s	E= k x (0.0016) x [(U/2.2)^1.3 / (M/2)^1.4] AP42, Section 13.2.4 AP-42, S13.2.4, particle size < 30 um, 1/95 ed Material Moisture Content (M) : 2% Max. handling capacity for each barging point: 473Mg/hr Number of barging points for Nam Cheong Works Area: 2 Unloading within the tipping hall with enclosures on three sides in addition to a top cover, water spray and flexible dust curtain will be provided at discharging point. 90% reduction of dust emission assumed.
	Unloading of spoils by trucks to barge for West Kowloon Terminus Works Area	E =3.54x10^-^4kg/Mg = 4.26664 X 10^-^3 g/s	E= k x (0.0016) x [(U/2.2)^1.3 / (M/2)^1.4] AP42, Section 13.2.4 AP-42, S13.2.4, particle size < 30 um, 1/95 ed Material Moisture Content (M) : 5% Max. handling capacity for each barging point: 434Mg/hr Number of barging points for West Kowloon Terminus at Nam Cheong Works Area: 1 Unloading within the tipping hall with enclosures on three sides in addition to a top cover, water spray and flexible dust curtain will be provided at discharging point. 90% reduction of dust emission assumed.
	Paved haul road -Transport the spoil to the Barging Point (The paved haul road served for 2 ramps, therefore, number of trucks on each section of the haul road would be different.)	E = 947 g/VKT =1.97363 x 10^-^4 g/m/s (for 360 truck trips) =3.94727 x 10^-^4 g/m/s (for 720 truck trips)	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12 g/m^2 Averaged truck weight: 16 tons No. of truck trips: 360 to 720 truck trips/day 97.5% reduction by watering haul road once per hour and keeping paved haul roads in wet condition. AP42, Section 13.2.1.
Temporary Stockpile Area at Nam Cheong Barging Points (Emergency Use)	Loading & unloading of materials	E=2.69 Mg/hectare /month of activity =1.55671 x 10^-5 g/m^2/s	30% area actively operating 75% reduction by complete watering coverage of active construction area four times a day AP42, Section 13.2.3
	Wind Erosion (night time)	E=0.85Mg/hectare /year =8.08600 x 10^-^7 g/m^2/s	30% active site AP42, Table 11.9.4

Table 12.14 Emission Factors for Dusty Construction Activities at Shek Kong Works Area

Emission Source	Activity	Emission Rate	Remarks
Construction Site for cut-cover section of Project Alignment and ventilation building	Cut and Cover Areas and Stockpile Areas	E=2.69 Mg/hectare /month of activity =3.11343 x 10^-6 g/m^2/s	15% area actively operating 90% reduction by complete watering coverage of active construction area ten times a day AP42, Section 13.2.3
	Wind Erosion (night time)	E=0.85Mg/hectare /year =4.04300 x 10^-^7 g/m^2/s	15% active site AP42, Table 11.9.4
	Paved Haul Road within Shek Kong site	E = 947 g/VKT =4.01305 x 10^-^4 g/m/s (for 732 truck trips) =2.30257 x 10^-4 g/m/s (for 420 truck trips)	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12 g/m^2 Averaged truck weight: 16 tons No. of truck trips: 420-732 truck trips/day 97.5% reduction by watering the paved haul roads once per hour and keeping the haul road in wet condition. AP42, Section 13.2.1
	Paved Haul Road within Tse Uk Tsuen Works Area	E = 947 g/VKT =1.57891 x 10^-^4 g/m/s	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12 g/m^2 Averaged truck weight: 16 tons No. of truck trips: 72 truck trips/day 90% reduction by water spraying to keep wet condition on paved haul roads AP42, Section 13.2.1
	Paved Haul Road within Pak Heung Works Area	E = 947 g/VKT =3.15781 x 10^-^4 g/m/s	E=k´(sL/2)^0.65´(W/3)^1.5 Particle size multiplier: 24g/VKT Silt content: 12 g/m^2 Averaged truck weight: 16 tons No. of truck trips: 288 truck trips/day 95% reduction by water spraying to keep wet condition on paved haul roads and the wheels of the trucks would be washed before entering the site. AP42, Section 13.2.1

12.57 The design emission concentrations of the dust collectors for cement/PFA silos and mixers of the concrete batching plant would follow the recommendation in Table 12.12. As advised by the Project Proponent, an active operation area of 15% is assumed for cut and cover areas at West Kowloon works area, West Kowloon Terminus sites and Shek Kong works area; and 30% is assumed for cut and cover areas at Nam Cheong works area. For the prediction of maximum daily average TSP concentration and annual average TSP concentration, 12-hour (07:00-19:00) per day is assumed for the construction period in the assessment.

Dispersion Modelling & Concentration Calculation

12.58 Fugitive Dust Model (FDM) (1993 version) is adopted to assess potential dust impact from the construction works. The worst case meteorological condition is used to predict the maximum 1-hour and 24-hour average TSP concentrations at representative discrete ASRs in the vicinity of the construction sites. The height of 1.5m (the breathing level of human), 5m, and 10m above ground are adopted for the construction dust impact assessment. For West Kowloon works area, higher assessment levels, 20m, 30m and 40m above ground levels are also assessed.

· Wind speed: 1 m/s

· Wind direction: 360 wind directions

· Stability class: D (daytime) & F (night time)

· Surface roughness: 1m

· Mixing height: 500 m

12.59 The background TSP level of 103 mg/m³, based on the latest five years average monitoring data from EPD Yuen Long monitoring station, is adopted as an indication of the TSP background concentration at Shek Kong works area during construction phase; while the background TSP level of 81 mg/m³, based on the latest five years monitoring data from EPD Sham Shui Po monitoring station, is adopted as indication of TSP background concentration at Nam Cheong and West Kowloon works areas during the construction phase.

12.60 For the prediction of the annual TSP concentrations due to the Project, Year 2005 meteorological data of King’s Park Weather Station are adopted for prediction of the annual average TSP concentrations at the discrete ASRs in the vicinity of West Kowloon works area and Nam Cheong works area. Year 2006 and 2007 data of this weather station are not used as the valid data in these two years are less than 90%. For Shek Kong works area, as the valid meteorological data in past few years at Shek Kong weather station is less than 90% in a year, Year 2006 meteorological data of Lau Fan Shan weather station which is another nearest station to the study area are applied for prediction of the annual average TSP concentrations at the sensitive receivers in the vicinity of Shek Kong works area.

12.61 Actually, there are no construction activities operated on Sundays and the public holidays. For the annual TSP concentration prediction, the hours from 0700 to 1900 in the year excluding these days are adopted for assessment of the daytime construction activities; while the hours from 1900 to 0700 in the year and the hours during Sunday and the public holidays are adopted for impact assessment of wind erosion on the sites. For the temporary stockpile area at Nam Cheong Barging Points, it would be for emergency use when the barging points cannot be operated (e.g. Typhoon No.3 or above hoist). Therefore, this temporary stockpile is considered to be operated for a month (in summer season) in the annual TSP prediction. Regarding the Shek Kong works area, the bulk excavation period for ERS at Shek Kong and Shek Kong Stabling Sidings would be last for 8 months (from October 2011 to May 2012) only and the construction activities in the remaining period would be superstructure construction works which are not dusty construction activities. This factor has taken into account in the annual prediction for the ASRs in the vicinity of Shek Kong works area.

12.62 Maximum emission rates of dusty construction activities are considered in all operation hours in the modelling. However, the emissions from dusty construction activities would not be always in the maximum rate as confirmed from the engineer. Therefore, there is a reduction of 50% in the annual concentrations prediction assuming that the normal emission rates of dusty construction activities would be half of the peak dust emission rates.

Operation Phase

12.63 As there is no significant air quality impact during operation of the Project and PTI, qualitative approach is adopted to address the air quality implications.

Prediction and Evaluation of Impacts

Construction Phase

West Kowloon Works Area (including WKT)

12.64 The predicted cumulative maximum hourly and daily average TSP concentrations at the representative ASRs due to construction activities at West Kowloon works area are presented in Tables 12.15 and 12.16.

12.65 Based on the results indicated in Tables 12.15 and 12.16, the predicted maximum 1-hour and 24-hour average TSP concentrations at all representative ASRs would comply with the criteria in EIAO-TM and AQO. The contour plots at 1.5m, 10m and 20m above ground level (AGL) are presented. The contour plots of 1-hour and 24-hour average TSP concentrations at 1.5m above ground level are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/110 to 115 and NOL/ERL/300/C/XRL/ENS/M60/210 to 215. The contour plots at 10m above ground are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/131 to 136 and NOL/ERL/300/C/XRL/ENS/M60/231 to 236. The contour plots at 20m above ground are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/161 to 166 and NOL/ERL/300/C/XRL/ENS/M60/261 to 266. All representative ASRs would comply with the criteria in EIAO-TM and AQO in the contour plots at 1.5m, 10m, and 20m above ground level. There is no ASR near the West Kowloon waterfront promenade where the dust criteria are not met during the construction phase of the Project. Therefore, there are no ASRs found to have non-compliance of the 1-hour and 24-hour average TSP criteria in the contour plots at 1.5m, 10m and 20m above ground level.

Table 12.15 Predicted Cumulative Maximum Hourly Average TSP Concentrations at Representative Air Sensitive Receivers (West Kowloon Works Area)

ASRs	Cumulative Maximum Hourly Average TSP Concentrations in mg/m^3
	1.5m AGL	5m AGL	10m AGL	15m AGL	20m AGL	30m AGL	40m AGL
MKA1	96	97	97	96	96	94	92
MKA2	98	99	98	98	97	95	93
WKA1	113	114	112	110	107	102	96
WKA2	108	109	108	106	104	100	96
WKA3	-	-	-	126	117	104	96
WKA5	209	213	261	351	365	153	96
WKA6	-	-	-	125	118	105	96
WKA7	-	-	-	-	-	106	96
WKA8	-	-	-	130	120	106	96
WKA9	138	138	130	122	114	102	95

Note: 1. The background TSP level of 81 mg/m³ has been included in the above results.

2. The air sensitive uses at WKA3, WKA6 and WKA8 are not less than 15m AGL; air sensitive uses at WKA7 are not less than 30m AGL.

Table 12.16 Predicted Cumulative Maximum 24-Hour Average TSP Concentrations at Representative Air Sensitive Receivers (West Kowloon Works Area)

ASRs	Cumulative Maximum 24-Hour Average TSP Concentrations in mg/m^3
	1.5m AGL	5m AGL	10m AGL	15m AGL	20m AGL	30m AGL	40m AGL
MKA1	90	90	90	90	89	88	87
MKA2	91	91	91	90	90	89	87
WKA1	99	100	99	97	95	92	89
WKA2	96	97	96	95	94	91	89
WKA3	-	-	-	105	99	92	88
WKA5	148	149	172	217	223	117	88
WKA6	-	-	-	104	100	93	88
WKA7	-	-	-	-	-	94	89
WKA8	-	-	-	106	100	93	89
WKA9	114	113	108	103	98	92	88

Note: 1. The background TSP level of 81 mg/m³ has been included in the above results.

2. The air sensitive uses at WKA3, WKA6 and WKA8 are not less than 15m AGL; air sensitive uses at WKA7 are not less than 30m AGL.

Table 12.17 Predicted Contributions to Annual Average TSP Concentrations at Representative Air Sensitive Receivers (West Kowloon Works Area) from the Project

ASRs	Annual Average TSP Concentrations in mg/m^3 due to the Project
	1.5m AGL	5m AGL	10m AGL	15m AGL	20m AGL	30m AGL	40m AGL
MKA1	0.07	0.07	0.07	0.07	0.06	0.06	0.05
MKA2	0.08	0.09	0.08	0.08	0.08	0.07	0.06
WKA1	0.17	0.18	0.17	0.15	0.14	0.11	0.09
WKA2	0.17	0.17	0.16	0.15	0.14	0.11	0.09
WKA3	-	-	-	0.74	0.53	0.32	0.22
WKA5	1.29	1.25	1.21	1.34	1.33	0.60	0.29
WKA6	-	-	-	2.18	1.77	1.17	0.77
WKA7	-	-	-	-	-	1.04	0.66
WKA8	-	-	-	1.65	1.20	0.70	0.45
WKA9	0.52	0.52	0.44	0.37	0.32	0.23	0.17

Note: 1. The background TSP level is 81 mg/m³.

2. The air sensitive uses at WKA3, WKA6 and WKA8 are not less than 15m AGL; air sensitive uses at WKA7 are not less than 30m AGL.

12.66 The annual average TSP concentrations at the representative ASRs due to construction activities at West Kowloon works area are predicted and presented in Table 12.17. The maximum contribution to the annual average TSP concentrations from the Project would be 2.18 mg/m³ (2.73% of the annual TSP AQO) occurring at ASR WKA6 at 15m AGL. The contributions to the annual average TSP concentrations at other representative ASRs from the Project would be increased by 0.05 – 1.77 mg/m³ (0.06% - 2.21% of the annual TSP AQO). The dust impacts from the construction activities on the ASRs are considered insignificant. The contour plots of annual TSP concentrations at 1.5m above ground level are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/410 to 415. The contour plots at 10m above ground are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/431 to 436. The contour plots at 20m above ground are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/461 to 466. As the worst hit level for ASR WKA6 and WKA8 are predicted at 15m AGL, the contour plots for the area in the vicinity of these ASRs are presented in Appendix 12-2. Referring to the contours of annual TSP concentrations at 1.5m AGL, 10m AGL, 15m AGL and 20m AGL, there are no ASRs with impact greater than 2.18 mg/m³.

Nam Cheong Works Area

12.67 The predicted cumulative maximum hourly and daily average TSP concentrations at the representative ASRs due to construction activities at Nam Cheong works area are presented in Tables 12.18 and 12.19.

12.68 Based on the results indicated in Tables 12.18 and 12.19, the predicted maximum 1-hour and 24-hour average TSP concentrations at all representative ASRs would comply with the criteria in EIAO-TM and AQO. It is noted that the worst levels would be at 1.5m above ground level. The contour plots of 1-hour and 24-hour average TSP concentrations at 1.5m above ground level are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/107 to 109 and NOL/ERL/300/C/XRL/ENS/M60/207 to 209. There are no ASRs found to have non-compliance of the 1-hour and 24-hour average TSP criteria in the contour plots.

Table 12.18 Predicted Cumulative Maximum Hourly Average TSP Concentrations at Representative Air Sensitive Receivers (Nam Cheong Works Area)

ASRs	Cumulative Maximum Hourly Average TSP Concentrations in mg/m^3
	1.5m AGL	5m AGL	10m AGL
NCA4	96	97	96
NCA5	142	128	107
NCA6	128	127	118
NCA7	149	144	126
NCA8	126	-	-

Note: 1. The background TSP level of 81 mg/m³ has been included in the above results.

2. ASR NCA8 is one-storey high.

Table 12.19 Predicted Cumulative Maximum 24-Hour Average TSP Concentrations at Representative Air Sensitive Receivers (Nam Cheong Works Area)

ASRs	Cumulative Maximum 24-Hour Average TSP Concentrations in mg/m^3
	1.5m AGL	5m AGL	10m AGL
NCA4	89	90	89
NCA5	114	106	95
NCA6	107	106	100
NCA7	116	113	104
NCA8	105	-	-

Note: 1. The background TSP level of 81 mg/m³ has been included in the above results.

2. ASR NCA8 is one-storey high.

Table 12.20 Predicted Contributions to Annual Average TSP Concentrations at Representative Air Sensitive Receivers (Nam Cheong Works Area) from the Project

ASRs	Annual Average TSP Concentrations in mg/m^3 due to the Project
	1.5m AGL	5m AGL	10m AGL
NCA4	0.02	0.02	0.02
NCA5	1.44	1.07	0.61
NCA6	0.36	0.35	0.29
NCA7	1.19	1.06	0.78
NCA8	1.99	-	-

Note: 1. The background TSP level is 81 mg/m³.

2. ASR NCA8 is one-storey high.

12.69 The annual average TSP concentrations at the representative ASRs due to construction activities at Nam Cheong works area are also predicted and presented in Table 12.20. The predicted maximum contribution to the annual average TSP concentrations from the Project would be 1.99 mg/m³ (2.49% of annual TSP AQO) occurring at ASR NCA8 at 1.5m AGL. The predicted contributions to the annual average TSP concentrations at other representative ASRs from the Project would be increased by 0.02 – 1.44 mg/m³ (0.03% - 1.8% of annual TSP AQO) only. The dust impacts arising from the Project to the ASRs are considered insignificant. The contour plots of annual TSP concentrations at 1.5m above ground level are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/407 to 409. Referring to the contours of annual TSP concentrations at 1.5m AGL, there are no ASRs with impact greater than 1.99 mg/m³.

Shek Kong Works Area

12.70 The predicted cumulative maximum hourly and daily average TSP concentrations at the representative ASRs due to construction activities at Shek Kong works area are presented in Tables 12.21 and 12.22.

12.71 Based on the results indicated in Tables 12.21 and 12.22, the predicted 1-hour and 24-hour average TSP concentrations at all representative ASRs would comply with the criteria in EIAO-TM and AQO. It is noted that the worst levels would be at 1.5m above ground level. The contour plots of 1-hour and 24-hour average TSP concentrations at 1.5m above ground level are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/101 to 106 and NOL/ERL/300/C/XRL/ENS/M60/201 to 206. There are no ASRs outside the construction work site boundary found to have non-compliance of the 1-hour and 24-hour average TSP criteria in the contour plots. Since the properties within the construction work site boundary would all under the land requirement plan, therefore, there is no ASRs inside the construction site boundary where the air quality criteria are not met.

Table 12.21 Predicted Cumulative Maximum Hourly Average TSP Concentrations at Representative Air Sensitive Receivers (Shek Kong Works Area)

ASRs	Cumulative Maximum Hourly Average TSP Concentrations in mg/m^3
	1.5m AGL	5m AGL	10m AGL
PHA1	129	129	124
PHA2	251	177	128
SSA1	162	150	139
SSA1a	150	149	140
SSA1b	172	162	144
SSA2	142	141	134
SSA3	146	146	139
SSA4	147	143	134
SSA5	125	126	125
SSA7	146	145	138
SSA8	129	128	124
SSA9	163	150	140
SSA10	173	167	151
SSA11	152	149	139
SSA12	146	140	133
TUA1	137	128	118
TUA2	171	136	118

Note: The background TSP level of 103 mg/m³ has been included in the above results.

Table 12.22 Predicted Cumulative Maximum 24-Hour Average TSP Concentrations at Representative Air Sensitive Receivers (Shek Kong Works Area)

ASRs	Cumulative Maximum 24-Hour Average TSP Concentrations in mg/m^3
	1.5m AGL	5m AGL	10m AGL
PHA1	116	116	114
PHA2	178	140	116
SSA1	135	129	123
SSA1a	130	129	123
SSA1b	140	134	125
SSA2	123	123	119
SSA3	126	126	122
SSA4	128	125	120
SSA5	115	115	115
SSA7	126	125	121
SSA8	117	117	114
SSA9	139	130	123
SSA10	139	136	128
SSA11	128	127	121
SSA12	127	124	119
TUA1	122	117	111
TUA2	138	120	112

Note: The background TSP level of 103 mg/m³ has been included in the above results.

Table 12.23 Predicted Contributions to Annual Average TSP Concentrations at Representative Air Sensitive Receivers (Shek Kong Works Area) from the Project

ASRs	Cumulative Annual Average TSP Concentrations in mg/m^3 due to the Project
	1.5m AGL	5m AGL	10m AGL
PHA1	0.06	0.06	0.05
PHA2	1.13	0.43	0.13
SSA1	0.78	0.49	0.26
SSA1a	0.36	0.30	0.21
SSA1b	2.34	1.36	0.56
SSA2	1.21	1.10	0.79
SSA3	0.48	0.41	0.28
SSA4	0.60	0.48	0.32
SSA5	0.16	0.16	0.14
SSA7	1.42	1.13	0.65
SSA8	0.37	0.35	0.27
SSA9	2.00	0.89	0.42
SSA10	0.94	0.78	0.47
SSA11	1.41	1.25	0.85
SSA12	0.66	0.55	0.38
TUA1	0.37	0.30	0.20
TUA2	0.96	0.45	0.20

Note: The background TSP level is 103 mg/m³.

12.72 The annual average TSP concentrations at the representative ASRs due to construction activities at Shek Kong works area are also predicted and presented in Table 12.23. The predicted maximum contribution to annual average TSP concentrations from the Project would be 2.34 mg/m³ (2.93% of annual TSP AQO) occurring at ASR SSA1b at 1.5m AGL. The predicted contributions to the annual average TSP concentrations at other representative ASRs from the Project would be increased by 0.05 – 2 mg/m³ (0.06 – 2.5% of annual TSP AQO) only. Since the major dusty activities, bulk excavation at Shek Kong works area, would be last for 8 months only, and the predicted maximum hourly and 24-hour average TSP concentrations at all representative ASRs would comply with the criteria in EIAO-TM and AQO, the dust impact arising from the Project to the ASRs is considered insignificant. The contour plots of annual TSP concentrations at 1.5m above ground level are indicated in Figure Nos. NOL/ERL/300/C/XRL/ENS/M60/401 to 406. Referring to the contours of annual TSP concentrations at 1.5m AGL, there are no ASRs with impact greater than 2.34 mg/m³.

Barging Points at Rambler Channel, Siu Lam, Lung Kwu Sheung Tan and Tsing Chau Tsai

12.73 The potential dust emission sources during the operation of the barging points at the captioned works areas would be dust emissions from trucks on the paved haul roads, unloading of spoils to the barges, materials handling and wind erosion at the active temporary stockpile areas. With the implementation of dust suppression measures as mentioned in Tables 12.10 and 12.11, no adverse dust impacts would be expected at the ASRs in the vicinity of these four barging points.

Adits / Vent Shafts (excluding Nam Cheong Vent Shaft), Ventilation Buildings and Tai Kong Po Emergency Access Point

12.74 Except Nam Cheong vent shaft, the size of the adits/shafts, ventilation buildings and the building for Tai Kong Po Emergency Access Point are limited. Less dusty activities to be conducted during construction of the superstructures (for ventilation buildings). With the implementation of dust suppression measures stipulated in Air Pollution Control (Construction Dust) Regulation, no adverse dust impacts would be anticipated at the nearby ASRs.

Shek Kong Stabling Sidings

12.75 The construction of SSS would involve minor excavation works and filling works. With the implementation of mitigation measures stipulated in the Air Pollution Control (Construction Dust) Regulation such as regular water spraying on exposed sandfill area, significant dust impact on the nearby ASRs is not expected.

Operation Phase

12.76 There is no adverse air quality impact expected from the operation of the Project and proposed diesel locomotive as discussed in Section 12.47 – 12.49.

12.77 The mechanical ventilation systems would be provided for the semi-confined PTI such that the air quality inside the PTI would comply with EPD guideline. The directions of the louvers would be located away from the nearby existing and planned ASRs as possible (i.e. facing seaside) and meet the requirements stipulated in EPD Practice Note for Professional Persons – Control of Air Pollution in Semi-Confined Public Transport Interchange (ProPECC PN 1/98), air pollution problem from arising is not anticipated.

Recommended Air Quality Mitigation Measures

12.78 Dust control measures have been incorporated into the engineering design as presented in Tables 12.9 to 12.14. For concrete batching plant, the requirements and mitigation measures stipulated in the Guidance Note on the Best Practicable Means for Cement Works (Concrete Batching Plant) BPM 3/2(93) should be followed and implemented. In addition, implementation of dust suppression measures stipulated in the Air Pollution Control (Construction Dust) Regulation and good site practices should be carried out to further minimize construction dust impact.

· Use of regular watering, with complete coverage, to reduce dust emissions from exposed site surfaces and unpaved roads, particularly during dry weather.

· Use of frequent watering for particularly dusty construction areas and areas close to ASRs.

· Side enclosure and covering of any aggregate or dusty material storage piles to reduce emissions. Where this is not practicable owing to frequent usage, watering shall be applied to aggregate fines.

· Open stockpiles shall be avoided or covered. Where possible, prevent placing dusty material storage piles near ASRs.

· Tarpaulin covering of all dusty vehicle loads transported to, from and between site locations.

· Establishment and use of vehicle wheel and body washing facilities at the exit points of the site.

· Provision of wind shield and dust extraction units or similar dust mitigation measures at the loading points, and use of water sprinklers at the loading area where dust generation is likely during the loading process of loose material, particularly in dry seasons/ periods.

· Imposition of speed controls for vehicles on unpaved site roads. 8 kilometers per hour is the recommended limit.

· Where possible, routing of vehicles and positioning of construction plant should be at the maximum possible distance from ASRs.

· Every stock of more than 20 bags of cement or dry pulverised fuel ash (PFA) should be covered entirely by impervious sheeting or placed in an area sheltered on the top and the 3 sides.

· Cement or dry PFA delivered in bulk should be stored in a closed silo fitted with an audible high level alarm which is interlocked with the material filling line and no overfilling is allowed.

· Loading, unloading, transfer, handling or storage of bulk cement or dry PFA should be carried out in a totally enclosed system or facility, and any vent or exhaust should be fitted with an effective fabric filter or equivalent air pollution control system.

Evaluation of Residual Impacts

Construction Phase

12.79 With the implementation of the mitigation measures as stipulated in the Air Pollution Control (Construction Dust) Regulation, dust control measures and good site practices, the predicted cumulative maximum 1-hour and 24-hour average TSP concentrations (including the background levels as mentioned in Section 12.59) at the ASRs in the vicinity of the construction sites would comply with the TSP criterion in EIAO-TM and AQO.

12.80 The predicted annual average TSP concentrations at the ASRs in the vicinity of West Kowloon works area and Nam Cheong works area induced by the construction activities of the Project would be increased by 0.02 to 2.18 mg/m³. There is no EPD monitoring station located in the vicinity of these work sites, therefore, the annual background TSP level at West Kowloon works area and Nam Cheong works area make reference to the latest 5-year data (Year 2003 – 2007) of the nearest EPD monitoring station at Sham Shui Po. It is noted that the annual background TSP level at this monitoring station is 81 µg/m³, which has exceeded the annual TSP AQO (80 mg/m³). However, the monitoring data at this station may not fully reflect the actual situation of the study areas. The EPD Sham Shui Po monitoring station is located at inland area but the Project sites at West Kowloon and Nam Cheong are located near the waterfront and open areas. Better air dispersion of the air pollutants is anticipated at these works areas comparing with the environment of EPD Sham Shui Po monitoring station. Taking into account the contributions from the construction activities of the Project at these works sites would only be 0.03% - 2.73% of the annual TSP AQO with the implementation of the proposed dust suppression measures, it is reasonable concluded that the residual dust impacts at the ASRs are acceptable.

12.81 The predicted annual average TSP concentrations at the ASRs in the vicinity of Shek Kong works area induced by the construction activities of the Project would be increased by 0.05 to 2.34 µg/m³. There is no EPD monitoring station located in the vicinity of Shek Kong works area. The annual background TSP level therefore makes reference to the latest 5-year data (Year 2003 – 2007) of the nearest EPD Monitoring Station at Yuen Long. The annual background TSP level at this monitoring station is 103µg/m³, which is already in excess of annual TSP AQO (80 mg/m³). In fact, Shek Kong is a rural area with village type developments and no any major industries within the area. Nevertheless, Yuen Long is a new town with industries developments such as Tung Tau Industrial Area and Yuen Long Industrial Estate. The adoption of the monitoring data at EPD Yuen Long monitoring station as background TSP level for Shek Kong works area may not be appropriate. The TSP levels arising from the dusty construction activities at Shek Kong works area would be 0.06% – 2.93% of the annual TSP AQO, it is reasonably concluded that the implementation of the above proposed extensive dust suppression measures would reduce the contribution impacts from the construction works to within the acceptable limit.

12.82 The following points should be noted with reference to EIAO-TM Clause 4.4.3 with regards to the residual dust impacts at the ASRs.

(i) Effects on public health and health of biota or risk to life

12.83 The nuisance effects associated with elevated dusts include reduced visibility, coating and soiling of surfaces leading to annoyance, loss of amenity, coating of vegetation and contamination of soils leading to changes in growth rates of vegetation, and irritation of the eyes. In this assessment, the predicted maximum 1-hour and 24-hour average TSP concentrations (including background levels) at the ASRs would all well below the EIAO-TM criterion and AQO. The maximum contributions to the annual TSP concentrations at the representative ASRs would be about 2.18 mg/m³ at West Kowloon works area, 1.99 mg/m³ at Nam Cheong works area, and 2.34 mg/m³ at Shek Kong works area. As the additional TSP levels induced from the Project to the existing background levels would be a few micrograms, no adverse nuisance to human is expected.

(ii) The magnitude of adverse environmental impacts

12.84 Based on the modelling results, the predicted worst annual TSP concentrations at representative ASRs due to dusty construction activities of the Project are:

Works Area	West Kowloon	Nam Cheong	Shek Kong
Representative ASRs ID	WKA6	NCA8	SSA1b
Predicted Maximum Contribution to Annual TSP Concentration from the Project during construction phase (mg/m^3)	2.18 (2.73% of annual TSP AQO)	1.99 (2.49% of annual TSP AQO)	2.34 (2.93% of annual TSP AQO)

12.85 As mentioned in Section 12.80 and 12.81, the TSP levels arising from the construction phase of the Project would not pose adverse air quality impact to the ASRs.

(iii) The geographic extent of the adverse environmental impacts

12.86 As mentioned in Section 12.80 and 12.81, there are no adverse environmental impacts during the construction phase of the Project.

(iv) The duration and frequency of the adverse environmental impacts

12.87 The TSP levels at the ASRs induced from the construction of the Project would only be 0.02 to 2.34 mg/m³. The potential dust impacts from West Kowloon works area and Nam Cheong works area would be less than 3 years. The potential dust impacts at the ASRs in the vicinity of Shek Kong works area would be about 8 months.

(v) The degree to which adverse environmental impacts are reversible or irreversible.

12.88 For the Project itself, the potential dust impacts are not considered as adverse environmental impacts as the predicted 1-hour and 24-hour average TSP levels at all representative ASRs would comply with EIAO-TM criterion and AQO with the implementation of proposed dust suppression measures. The contribution to annual TSP prediction from the Project would only be 0.03% - 2.93% of annual TSP AQO. It would not have potential dust impacts to the ASRs once the dusty construction activities have completed, it is considered as short-term impacts.

(vi) The ecological context

12.89 The potential dust impacts arising from the Project would not involve any ecological context.

(vii) The degree of disruption to sites of cultural heritage

12.90 The potential dust impacts arising from the Project would not involve any cultural heritage context.

(viii) International and regional importance

12.91 The potential dust impacts arising from the Project would not involve any international and regional importance.

(ix) Both the likelihood and degree of uncertainty of adverse environmental impacts

12.92 The background TSP concentrations adopted in the assessment is based on the past 5-year (2003 to 2007) average data recorded at the nearest EPD air quality monitoring stations in accordance with EPD’s Guidelines on Assessing the ‘TOTAL’ Air Quality Impacts. As these stations are not exactly located at the Project works areas, the past monitoring data may not be fully reflect the actual background levels at these works areas.

Operation Phase

12.93 Insignificant air quality impact from operation of diesel locomotives at SSS is anticipated. No adverse air quality impact during the operation of the PTI is expected with the proper design of mechanical air ventilation system.

Environmental Monitoring and Audit Requirements

12.94 Environmental monitoring and audit for dust emission should be conducted during the construction phase of the Project so as to check compliance with legislative requirements. Details of the monitoring and audit programme are contained in a stand-alone EM&A Manual.

Conclusion

Construction Phase

12.95 Potential air quality impacts from the construction works for the Project would mainly be related to construction dust from excavation, materials handling, spoil removal and wind erosion, as well as operation of concrete batching plant, stockpiles and barging facilities. With the implementation of mitigation measures in the Air Pollution Control (Construction Dust) Regulation, proposed dust suppression measures, good site practices and dust control measures for the Specified Process (concrete batching plant), no adverse dust impacts on the ASRs would be anticipated.

Operation Phase

12.96 No adverse air quality impact expected from the operation of the Project and the proposed diesel locomotive at SSS. The mechanical air ventilation system for the proposed PTI has been designed in accordance with EPD Practice Note for Professional Persons – Control of Air Pollution in Semi-Confined Public Transport Interchange (ProPECC PN1/98), and air quality impact during its operation is therefore not anticipated.